Chip-based CPU cooler and cooling method thereof

ABSTRACT

Provided are chip-based CPU cooling device and cooling method thereof. The cooling device comprises a metal cover adapted to completely cover and contact the CPU, a hollow seat, a thermal electric cooler shaped to fit in the seat and adapted to contact the cover, a heat dissipation member (e.g., fins) enclosed by a housing and mounted on the seat for contacting the thermal electric cooler, a first fan mounted on top of the housing, and a second fan mounted on side of the housing. An optimum heat dissipation can be obtained by running a control program to control on/off of the fans and power of the thermal electric cooler by operating the cooling device in one of a plurality of corresponding temperature ranges of the CPU.

BACKGROUND OF THE INVENTION

1. Field of Invention The present invention generally relates to CPU(central processing unit) cooling devices and more particularly to achip-based CPU cooling device having a thermal electric cooler and acooling method thereof.

2. Description of Related Art

Operating frequency of the CPU of a computer has been continuouslyincreasing as the technology develops. Accordingly, heat generated by arunning CPU increases greatly. Heat dissipation thus has become acritical issue in maintaining the normal operation of a CPU (i.e.,computer).

Conventionally, a CPU cooler is implemented as a passive one. In detail,a member formed of high heat conduction metal or alloy is mounted on theCPU. The member comprises a plurality of parallel fins. In operation,heat generated by CPU is transferred to the fins by contact prior todissipating to the ambient. For achieving maximum heat dissipation, thenumber of fins, locations of the fins, angles of the fins with respectto CPU, convection, material of the cooler (i.e., heat conductivity ofmaterial) are considered. However, the desired good heat dissipation ofCPU is compromised as interference among heat conduction, convection,and radiation.

Another conventional CPU cooler is implemented as a thermal electriccooler which is in direct contact with CPU. A heat absorbing surface anda heat dissipating surface are formed on both sides of a semiconductorchip in response to electric current flowing through the thermalelectric cooler. The heat absorbing surface contacts the hot CPU and theheat dissipating surface is in fluid communication with a heat sink orcooling fan so as to carry out cooling of the CPU. Such technique isdisclosed in Taiwanese Patent No. 88,203,663. However, heat mayundesirably transfer back to the heat absorbing surface if coolingmembers arranged at the heat dissipating surface operate abnormally.Moreover, dew may generate on the cooler due to abrupt temperature drop.Thus, the need for improvement of thermal electric cooler for CPU stillexists.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide achip-based CPU cooling device having a metal cover completely coveredand contacted the CPU for facilitating heat dissipation by eliminatingexternal air interference.

It is another object of the present invention to provide a chip-basedCPU cooling device comprising a hollow seat and a housing each having anouter wall, an inner wall, and a groove defined by the walls fordirecting air communication with a cover or fins by eliminating externalair interference.

It is yet another object of the present invention to provide achip-based CPU cooling device comprising a thermal electric cooler, afirst fan mounted on a first outlet, and a second fan mounted on asecond outlet such that an optimum heat dissipation can be obtained byrunning a control program to optionally control on/off of the fans andpower of the activated thermal electric cooler depending on actualdemand.

In one aspect of the present invention, there is provided a chip-basedcooling device mountable on a CPU arranged on a motherboard, comprisinga metal cover, a hollow seat, a thermal electric cooler, a heatdissipation member, a housing, a first fan, and a second fan wherein thecover is adapted to completely cover and contact the CPU, the thermalelectric cooler is shaped to fit in the seat, the heat dissipationmember is enclosed by the housing and is mounted on the seat, the firstfan is mounted on top of the housing, the second fan is mounted on oneside of the housing, the thermal electric cooler is adapted to contactthe cover, and the heat dissipation member is adapted to contact thethermal electric cooler, and wherein the seat and housing each having anouter wall, an inner wall, and a groove defined by the walls fordirecting air communication with a cover or fin by eliminating externalair interference.

In another aspect of the present invention, in a chip-based coolingdevice mountable on a CPU arranged on a motherboard, the cooling deviceincluding a thermal electric cooler including a heat dissipating surfaceand a heat absorbing surface wherein electricity is produced by heatinga junction between the heat absorbing surface and the heat dissipatingsurface for producing an electromotive force for dissipating heat, afirst fan adapted to dissipate heat to the ambient, and a second fanadapted to draw external cold air into the cooling device there isprovided a method of cooling the CPU comprising the steps of a) definingan operating temperature of the CPU into one of a plurality of ranges;b) setting a plurality of operations of the first fan, the second fan,and the thermal electric cooler based on each range wherein in a firstrange each of the thermal electric cooler, the first fan, and the secondfan is off; in a second range each of the thermal electric cooler, thefirst fan, and the second fan is in a standby condition; in a thirdrange the thermal electric cooler operates in low power, the first fanis on, and the second fan is off; in a fourth range the thermal electriccooler operates in high power, the first fan is on, and the second fanis off; in a fifth range the thermal electric cooler operates in highpower, the first fan is on, and the second fan is on; and in a sixthrange the thermal electric cooler operates in full power, the first fanis on, and the second fan is on; c) measuring the operating temperatureof the CPU; and d) running a control program to determine acorresponding one of the ranges that the cooling device is about toperform.

In yet another aspect of the present invention, in a chip-based coolingdevice mountable on a CPU arranged on a motherboard, the cooling deviceincluding a thermal electric cooler including a heat dissipating surfaceand a heat absorbing surface wherein electricity is produced by heatinga junction between the heat absorbing surface and the heat dissipatingsurface for producing an electromotive force for dissipating heat, afirst fan adapted to dissipate heat to the ambient, and a second fanadapted to draw external cold air into the cooling device there isprovided a method of cooling the CPU comprising the steps of a) definingan operating temperature of the CPU into one of a plurality of ranges;b) setting a plurality of operations of the first fan, the second fan,and the thermal electric cooler based on each range wherein in a firstrange the thermal electric cooler operates in low power, the first fanis on, and the second fan is off; in a second range the thermal electriccooler operates in high power, the first fan is on, and the second fanis off; and in a third range the thermal electric cooler operates inhigh power, the first fan is on, and the second fan is on; c) measuringthe operating temperature of the CPU; d) running a control program todetermine a corresponding one of the ranges that the cooling device isabout to perform; and e) forming a cycle including the first, thesecond, and the third ranges such that a drop of the operatingtemperature of the CPU out of the third range is adapted to cause thecooling device to operate in the first range.

The above and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptiontaken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a preferred embodiment ofcooling device according to the invention to be mounted on a CPU;

FIG. 2 is a perspective view of one portion of the assembled coolingdevice shown in FIG. 1;

FIG. 3 is a perspective view of the remaining portion of the assembledcooling device shown in FIG. 1;

FIG. 4 is a perspective view of the completely assembled cooling deviceon the CPU shown in FIG. 1; and

FIG. 5 is a state diagram illustrating a plurality of temperature casesaccording to a cooling method of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 to 4, there is shown a cooling device for CPU inaccordance with a preferred embodiment of the invention. The coolingdevice comprises a cover 11 formed of metal of high heat conductivity, aseat 12, a thermal electric cooler 13, a frame 14, a plurality of fins21 of high heat conductivity as a heat sink, a housing 22, a first fan23, and a second fan 24. Each component is discussed in detailed below.

A CPU 3 is completely covered by the cover 11 thereon. The cover 11 alsocompletely contacts the CPU 3 and the thermal electric cooler 13. Thecover 11 is served to direct out heat produced from CPU 3. The squarehollow seat 12 comprises an outer U-shaped wall 121, an inner U-shapedwall 122, a U-shaped groove 123 defined by the walls 121 and 122 fordirecting air communication with the cover 11 (i.e., no external airinterference), and a central opening 124 which is a hollow-throughopening. A chip powered by flowing electric current therethrough isprovided in the thermal electric cooler 13 and the chip comprises alower heat absorbing surface 131 and an upper heat dissipating surface132. A lower portion of the thermal electric cooler 13 is shaped toneatly fit in the opening 124 to contact the cover 11.

The square frame 14 comprises a central opening 141 with an upperportion of the thermal electric cooler 13 neatly fitted therein andslightly, upwardly projected from the seat 12 (as shown in FIG. 3) tocontact the base of the fins 21. The housing 22 is secured to the seat12 (as shown in FIG. 4), which is in turn secured to a motherboard withthe CPU 3 mounted thereon in a manner known in the art. The housing 22,as shown in FIG. 1, comprises an outer wall 221, an inner wall 222, achannel 223 defined by the walls 221 and 222 for directing aircommunication with the fins 21 (i.e., no external air interference), acentral passageway 224 defined by the inner wall 222 for neatly fittingthe fins 21 therein, an upper opening 225 with the first fan 23 mountedthereon, and an inclined passage 226 at one side, the passage 226 havingan opening 227 at an open end with the second fan 24 mounted thereon.This completes the assembly of the cooling device for CPU on themotherboard, as shown in FIG. 4. Note that the fins 21 may be replacedby any of other good heat dissipation members (e.g., heat pipe) in otherembodiments.

In operation, heat generated by the running CPU 3 is transferred to theheat dissipating surface 132 through the cover 11 and the heat absorbingsurface 131 by conduction in which electricity is produced by heatingthe junction between the heat absorbing surface 131 and the heatdissipating surface 132 so as to produce an electromotive force.Further, heat is transferred to the fins 21 from the heat dissipatingsurface 132 by conduction due to the electromotive force. At the sametime, the first fan 23 is powered to dissipate heat from the fins 21 tothe ambient via the passageway 224 and the second fan 24 is powered todraw external cold air onto the fins 21 in the passageway 227. Such cangreatly enhance the heat dissipation capability of the cooling device,resulting in a quick, sufficient cooling of the CPU 3.

Referring to FIG. 5, it shows a state diagram illustrating a pluralityof cases (six cases are shown) according to a cooling method of thecooling device of the invention. The cases are defined based on theoperating temperature of CPU 3. A first case 41 corresponds to theoperating temperature of CPU 3 smaller than 15° C. (i.e., temp<15° C.),a second case 42 corresponds to the operating temperature of CPU 3larger or equal to 15° C. and smaller than 25° C. (i.e., 15° C.≦temp<25°C.), a third case 43 corresponds to the operating temperature of CPU 3larger or equal to 25° C. and smaller than 36° C. (i.e., 25° C.≦temp<36°C.), a fourth case 44 corresponds to the operating temperature of CPU 3larger or equal to 36° C. and smaller than 41° C. (i.e., 36° C.≦temp<41°C.), a fifth case 45 corresponds to the operating temperature of CPU 3larger or equal to 41° C. and smaller or equal to 69.9° C. (i.e., 41°C.≦temp≦69.9° C.), and a sixth case 46 corresponds to the operatingtemperature of CPU 3 larger than 70° C. (i.e., 70° C.<temp)respectively. Predetermined operations of certain components (e.g., onor off of the first fan 23 and/or the second fan 24, and off, low poweroperation, or full (or high) power operation of the thermal electriccooler 13 of the cooling device will be activated immediately when theoperating temperature of CPU 3 reaches the temperature range of one ofthe cases. As a result, an optimum heat dissipation effect can becarried out as detailed below.

In the first case 41 the thermal electric cooler 13, the first fan 23,and the second fan 24 are all off. In the second case 42 the thermalelectric cooler 13, the first fan 23, and the second fan 24 are instandby condition. In the third case 43 the thermal electric cooler 13operates in low power (or in half power as in other preferredembodiment), the first fan 23 is on, and the second fan 24 is off. Inthe fourth case 44 the thermal electric cooler 13 operates in highpower, the first fan 23 is on, and the second fan 24 is off. In thefifth case 45 the thermal electric cooler 13 operates in high power, thefirst fan 23 is on, and the second fan 24 is on. In the sixth case 46the thermal electric cooler 13 operates in full power, the first fan 23is on, and the second fan 24 is on. Additionally, a temperature sensorincluding a thermometer (not shown) is provided between the cover 11 andthe CPU 3. The thermometer is adapted to measure the operatingtemperature of the CPU 3 and the temperature sensor is adapted to sendthe measured temperature to a control program which is, in turn, run todetermine a corresponding case of the cooling device (i.e., temperaturerange).

A cycle 51 including third, fourth, and fifth cases 43, 44, and 45 canbe formed. For example, a drop of the operating temperature of the CPU 3out of the range of 41° C. and 69.9° C. may cause the cooling device toleave the fifth case 45 to enter the third case 43 directly ascontrolled by the running control program. The cycle 51 thus can operatein a low noise and power saving mode. Moreover, state change can be madeeither from the first case 41 to the second case 42 or from the secondcase 42 to the first case 41 (i.e., reversible therebetween). Also,state change can be made either from the second case 42 to the thirdcase 43 or from the third case 43 to the second case 42. In addition,state change can be made either from the fifth case 45 to the sixth case46 or from the sixth case 46 to the fifth case 45.

Additionally, the operating temperature of CPU 3 and the operatingstatus of any component of the cooling device can be shown on thecomputer monitor immediately. For instance, an under temperature warningmay be issued when the CPU 3 is operating in the first case 41. Also, anover temperature warning may be issued when the CPU 3 is operating inthe sixth case 46. In brief, the above temperature cases are implementedas a finite state machine. Further, any change from one state to theother state is done by event driving in a logic flow. For instance, itis done by running a software called “STATE FLOW”.

While the invention herein disclosed has been described by means ofspecific embodiments, numerous modifications and variations could bemade thereto by those skilled in the art without departing from thescope and spirit of the invention set forth in the claims.

1. A chip-based cooling device mountable on a CPU arranged on amotherboard, comprising a metal cover, a hollow seat, a thermal electriccooler, a heat dissipation member, a housing, a first fan, and a secondfan wherein the cover is adapted to completely cover and contact theCPU, the cover is also adapted to contact a bottom of the thermalelectric cooler, the thermal electric cooler is shaped to fit in theseat, the housing is mounted on a top of the seat, the heat dissipationmember is enclosed by the housing, the first fan is mounted on a top ofthe housing, the second fan is mounted on a side of the housing, and abottom of the heat dissipation member is adapted to contact a top of thethermal electric cooler.
 2. The cooling device of claim 1, wherein eachof the seat and the housing comprises an outer wall, an inner wall, anda groove defined by the walls for direct air communication with thecover or the heat dissipation member.
 3. The cooling device of claim 2,wherein the seat further comprises a central opening for receiving thethermal electric cooler.
 4. The cooling device of claim 2, wherein thehousing further comprises a central passageway defined by the inner wallfor receiving the heat dissipation member, an upper opening with thefirst fan mounted thereon, and an inclined passage at one side, thepassage having an opening at an open end with the second fan mountedthereon.
 5. The cooling device of claim 4, wherein the first fan isadapted to dissipate heat to the ambient and the second fan is adaptedto draw external cold air into the housing.
 6. The cooling device ofclaim 1, further comprising a hollow frame comprising a central openingshaped to put the thermal electric cooler therein such that the thermalelectric cooler therein is adapted to upwardly project from the seat. 7.The cooling device of claim 1, wherein the heat dissipation member is aheat sink.
 8. The cooling device of claim 1, wherein the heatdissipation member is a heat pipe.
 9. In a chip-based cooling devicemountable on a CPU arranged on a motherboard, the cooling deviceincluding a thermal electric cooler including a heat dissipating surfaceand a heat absorbing surface wherein electricity is produced by heatinga junction between the heat absorbing surface and the heat dissipatingsurface for producing an electromotive force for dissipating heat, afirst fan adapted to dissipate heat to the ambient, and a second fanadapted to draw external cold air into the cooling device, a method ofcooling the CPU comprising the steps of: a) defining an operatingtemperature of the CPU into one of a plurality of ranges; b) setting aplurality of operations of the first fan, the second fan, and thethermal electric cooler based on each range wherein in a first rangeeach of the thermal electric cooler, the first fan, and the second fanis off; in a second range each of the thermal electric cooler, the firstfan, and the second fan is in a standby condition; In a third range thethermal electric cooler operates in low power, the first fan is on, andthe second fan is off; in a fourth range the thermal electric cooleroperates in high power, the first fan is on, and the second fan is off;in a fifth range the thermal electric cooler operates in high power, thefirst fan is on, and the second fan is on; in a sixth range the thermalelectric cooler operates in full power, the first fan is on, and thesecond fan is on; c) measuring the operating temperature of the CPU; andd) running a control program to determine a corresponding one of theranges that the cooling device is about to perform.
 10. In a chip-basedcooling device mountable on a CPU arranged on a motherboard, the coolingdevice including a thermal electric cooler including a heat dissipatingsurface and a heat absorbing surface wherein electricity is produced byheating a junction between the heat absorbing surface and the heatdissipating surface for producing an electromotive force for dissipatingheat, a first fan adapted to dissipate heat to the ambient, and a secondfan adapted to draw external cold air into the cooling device, a methodof cooling the CPU comprising the steps of: a) defining an operatingtemperature of the CPU into one of a plurality of ranges; b) setting aplurality of operations of the first fan, the second fan, and thethermal electric cooler based on each range wherein in a first range thethermal electric cooler operates in low power, the first fan is on, andthe second fan is off; in a second range the thermal electric cooleroperates in high power, the first fan is on, and the second fan is off;and in a third range the thermal electric cooler operates in high power,the first fan is on, and the second fan is on; c) measuring theoperating temperature of the CPU; d) running a control program todetermine a corresponding one of the ranges that the cooling device isabout to perform; and e) forming a cycle including the first, thesecond, and the third ranges such that a drop of the operatingtemperature of the CPU out of the third range is adapted to cause thecooling device to operate in the first range.
 11. In a chip-basedcooling device mountable on a CPU arranged on a motherboard, a method ofcooling the CPU comprising the steps of: a) defining an operatingtemperature of the CPU into one of a plurality of ranges; b) setting aplurality of operations of the first fan, the second fan, and thethermal electric cooler based on each range wherein in a first range thethermal electric cooler operates in low power, the first fan is on, andthe second fan is off; in a second range the thermal electric cooleroperates in high power, the first fan is on, and the second fan is off;in a third range the thermal electric cooler operates in high power, thefirst fan is on, and the second fan is on; and in a fourth range thethermal electric cooler operates in full power, the first fan is on, andthe second fan is on; c) measuring the operating temperature of the CPU;and d) running a control program to determine a corresponding one of theranges that the cooling device is about to perform.
 12. In a chip-basedcooling device mountable on a CPU arranged on a motherboard, a method ofcooling the CPU comprising the steps of: a) defining an operatingtemperature of the CPU into one of a plurality of ranges; b) setting aplurality of operations of the first fan, the second fan, and thethermal electric cooler based on each range wherein in a first range thethermal electric cooler operates in low power, the first fan is on, andthe second fan is off; in a second range the thermal electric cooleroperates in high power, the first fan is on, and the second fan is off;and in a third range the thermal electric cooler operates in high power,the first fan is on, and the second fan is on; c) measuring theoperating temperature of the CPU; d) running a control program todetermine a corresponding one of the ranges that the cooling device isabout to perform; and e) forming a cycle including the first, thesecond, and the third ranges such that a drop of the operatingtemperature of the CPU out of the third range is adapted to cause thecooling device to operate in the first range.